Biology B2.2 A - Keep out!

Question	Answer
What are the 3 types of defences out bodies have against pathogens?	Physical, chemic, & bacterial.
What are some examples of physical defences & how do they help?	Examples: The skin; mucus in the respiratory & digestive systems: platelets in blood. They help by preventing pathogens from invading our tissues
What are some examples of chemical defences & how do they help?	Examples: Stomach acid; enzymes & substances that kill microbes in salvia, mucus, & tears. They destroy pathogens & stop them producing.
What are some examples of bacterial defences & how do they help?	Examples: The skin; mucus in the respiratory & digestive systems; platelets in the blood. They prevent pathogens from invading our tissues.
What are some examples of chemical defences & how do they help?	Examples: stomach acid; enzymes & substances that kill microbes in saliva, mucus, & tears. They destroy pathogens & stop them from reproducing.
What are some examples of bacterial defences & how do they help?	Examples: Helpful bacteria that live on the skin & in the gut. They compete against pathogens by using up nutrients & space.
What is a non-specific defence?	A defence that is always present. They are not made in response to a specific pathogen.
What are platelets?	they are fragments of cells made from cytoplasm of large cells.
What do platelets do when a blood vessel is damaged?	They stick to the cut edge & send out substances that trigger a series of reactions, creating a blood lot @ the site.

Resource summary

	Created by lily bevan over 6 years ago